The present invention relates to a disposable manometer for use with a cardio-pulmonary resuscitator CPR bag. In the prior art, manometers are known, however, Applicant is unaware of any such device including all of the features and aspects of the present invention. Applicant is aware of U.S. Pat. No. 3,975,959 to Larkin which discloses a pressure gauge including a dial with an indicator pointer connected to a cylindrical follower having projections coupled with grooves formed in a stem portion connected to a movable wall. The movable wall is exposed to a source of air pressure and reciprocates the stem portion directly responsive to changes in air pressure to cause rotation of the follower and the pointer. The present invention differs from the teachings of Larkin as contemplating a rotatable pointer carried on a stem having an external spiral-shaped projection with a fixed stem coupling carried by a diaphragm. Furthermore, the inventive disposable manometer includes an elongated restricted passageway connecting the source of pressure to the manometer chamber. This restricted passageway acts to smooth out transient fluctuations in pressure so that the operation of the pointer is much smoother than is possible in the Larkin device which has the movable wall directly exposed, without restriction, to the source of pressure, and, thus, is susceptible to every minute variation in pressure from the source thereof such that operation of the pointer of Larkin cannot be as smooth as is the case in the present invention. In addition, the diaphragm of the present invention does not leak whereas the Larkin device is a piston type device that can leak air.
Applicant is also aware of the following U.S. Patents:
U.S. Pat. No. 2,271,268 to Longstreet
U.S. Pat. No. 4,020,784 to Greene
U.S. Pat. No. 4,821,713 to Bauman
U.S. Pat. No. 5,140,982 to Bauman
These references are believed to be of only general interest concerning the teachings of the present invention.